Inhibition by inhibitors of receptor interactions. A. Locations of mutations and reversions on the structure of gp120 relative to the receptors binding sites. In this orientation the cell membrane would be on top, the viral membrane below and allows a direct view on the CD4BS. The lower panels show a 90° rotated view, a view from the target membrane. Residue 418 is indicated in yellow, and residues 386 and 433 are indicated in red. The GlcNac2Man3 core pentose of the carbohydrate attached to N386 is indicated in cyan (modeled onto gp120 by Dr. Peter Kwong). The residues important for the interaction with CD4 and the coreceptor are indicated in blue and green, respectively. B. Inhibition of virus variants with sCD4 and AMD3100 on CD4+ enriched lymphocytes. Inhibition curves are depicted for each of the viruses in limiting dilutions of either sCD4 (left panel) or the CXCR4 inhibitor AMD3100 (right panel).